Unlike Jake LaMotta, who only worked in night clubs when he was way, way down (remember Raging Bull?), World Champion Jack Dempsey played three years in vaudeville when he — and it — were at the very top of the world. Colorado native Dempsey ran away from home at 16 and rode the rails as a hobo, earning his way by picking fights in saloons and mining camps. With Doc Kearns as his manager, he took the title in 1919 at age 24 and spent much of the early to mid twenties fighting exhibition matches, acting in silent movies and playing big time Keith vaudeville, usually performing comedy sketches and crosstalk with his wife and manager as partners. He finally lost his title in 1926. After a failed re-match the following year, Dempsey restricted himself to exhibition matches and running his New York restaurant. He passed away in 1983 at age 87.
To find out more about these variety artists and the history of vaudeville, consult No Applause, Just Throw Money: The Book That Made Vaudeville Famous, available at Amazon, Barnes and Noble, and wherever nutty books are sold.